Fluorescent compounds are important compounds because of their broad applications, and particularly because of their highly sensitive and specific detection methods. It is desirable to obtain fluorescent compounds that fluoresce in a wide range of colors so that specific compounds can be selected for different purposes. Rational design of compounds with specific emission wavelengths and high quantum yields is difficult.
Combinatorial chemistry is a synthetic strategy that produces diverse, usually large, chemical libraries. It is the systematic and repetitive, covalent connection of a set of different monomeric building blocks of varying structure to each other to produce an array of diverse molecules. It also encompasses other chemical modifications, such as cyclizations, eliminations, cleavages, etc., that are carried out in a manner that generates permutations and thus collections of diverse molecules.
Chemical combinatorial libraries are diverse collections of molecular compounds. These compounds are formed using a multi-step synthetic route wherein a series of different chemical modules can be inserted at any particular step in the route. By performing the synthetic route multiple times in parallel, each possible permutation of the chemical modules can be constructed. The result is the rapid synthesis of hundreds, thousands, or even millions of different structures within a chemical class.
Combinatorial synthetic and screening techniques can identify lead structures from a variety of library compounds, enhancing the success rate in developing useful new compounds while saving much time in trial and error. Following its application in drug discovery, the combinatorial approach now competes with rational design methods in the field of materials science.
While a combinatorial approach has been used in developing fluorescent libraries, the spectral properties and potential applications of the presently available combinatorial fluorescent libraries are still limited.
There is a great need to develop highly specific and rapid sensors/detectors for a variety of diseases (Combinatorial Chemistry-Synthesis, Analysis, Screening, June, Ed.; Wiley-VCH; Weinhein, Germany, 1999). Novel fluorescent libraries, which can recognize many different biological analytes and change their fluorescence properties, are of great interest. (Wurthner et al., Angew. Chem. Int. Ed, 1999, 38: 1649; Takasu et al., J. Comb. Chem, 2003, 5:211; Briehn et al., Angew. Chem. Int. Ed., 2001, 40: 4680; Szurdoki et al., Anal. Chem. 2000, 72:5250; Merrington et al., Chem. Commun., 2002, 140-141) Solid phase combinatorial synthesis and screening can identify lead structures from a variety of library compounds, enhancing success rate in developing fluorescent molecules while saving time.